The invention relates to a forming device for cup-shaped hollow bodies having a machine frame, a drive device, a workpiece rotary table for accommodating workpiece holders, which are formed to fix hollow bodies, and having a tool holder for accommodating processing tools, wherein workpiece rotary table and tool holder face one another and can be turned about a rotational axis in relation to one another and can be linearly moved in relation to one another along the rotational axis, wherein the drive device is designed for providing a rotary step movement and a cyclical linear movement between workpiece rotary table and tool holder, in order to enable the hollow bodies to be formed by means of the processing tools in a plurality of consecutive processing steps, and wherein the workpiece holder has a recess for accommodating a hollow body and a wall section, which limits the recess in certain areas, has an adjustable geometry, which is designed to narrow the cross-section of the recess, in order to enable the hollow body to be fixed on the workpiece holder.
A forming machine is known from EP 0 275 369 A2, with which cup-shaped hollow bodies made of metal, in particular aluminium, can be formed in certain areas, in particular drawn in locally, from an essentially cylinder sleeve shaped initial state, so that, for example, a closing cap or an atomizer valve can be fitted in a sealing manner in the area of the opening. The known forming machine has a machine frame, on which a supporting tube is formed. A workpiece rotary table is pivot-mounted on an outer surface of the supporting tube. A linearly movable guide tube is accommodated in a recess bounded by the supporting tube, to the end section of which linearly movable guide tube the workpiece rotary table is attached. A drive device is accommodated in the machine frame, which drive device is designed to produce an intermittent rotary movement of the workpiece rotary table and to produce an oscillating linear movement of the guide tube and the workpiece rotary table connected to it. By means of the linear movement, the tools provided on the workpiece rotary table, in particular forming tools, can be brought into engagement with the hollow bodies held on the workpiece rotary table, in order to locally process them, particularly in order to plastically deform them. By means of the intermittent rotary movement of the workpiece rotary table, the hollow bodies can be brought into contact with the tools, attached to the tool holder table, in serial order so as to form the hollow bodies step by step from a starting geometry to a target geometry. Before carrying out the processing the hollow bodies are fixed by means of workpiece holders attached to the workpiece rotary table, and after carrying out the processing they are released again. For this purpose the workpiece holder has a piston which can be pneumatically actuated and which acts on a circumferential, flexible ring in an axial direction and can at least partly displace the ring inwardly in the radial direction, thereby clamping the hollow body at an outer surface and thereby fixing it to the workpiece holder.